The presence and distribution of wood extractives can be related to the physicochemical properties of wood. Wood extractives are constituted of compounds that can easily migrate within the wood. Relocalisation of extractives occurs naturally during different wood treatments and processing. In this study the extractives influence on the wettability and swelling properties of thermally modified Scots pine (Pinus sylvestris L.) was investigated using a multicycle Wilhelmy plate method, which enables measurements of apparent contact angles, sorption dynamics and dimensional stability. Samples were prepared from matched boards of thermally modified wood (modified according to the ThermoWood®D process) and unmodified wood. Extracted samples were prepared by a Soxtec system using acetone and ethanol/toluene. Initial data showed that the contact angle for the TM samples was not much affected by the different extractions. The lowest dimensional stability was observed for the unmodified wood samples extracted with acetone. The liquid uptake for thermally modified wood was reduced for the samples extracted with acetone and acetone+ethanol/toluene compared with the non-extracted samples.
Keywords: Thermally modified wood, extractives, wettability, swelling
Authors
Källbom S.
Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, SWEDEN
Sedighi Moghaddam M.
SP Technical Research Institute of Sweden – Chemistry, Materials and Surfaces
Segerholm K.
Sustainable Built Environment, SP Technical Research Institute of Sweden, Stockholm, SWEDEN
Jones D.
Sustainable Built Environment, SP Technical Research Institute of Sweden, Stockholm, SWEDEN
Wålinder M.
Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, Stockholm, SWEDEN
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